Wearable Signals¶

WearableSignal is a four-state enum that represents how confident the app is that a given Samsung Health metric is being actively tracked by a wearable.

States¶

enum class WearableSignal {
    UNKNOWN,
    NO_DEVICE_LIKELY,
    DEVICE_PRESENT_NOT_WORN_RECENTLY,
    ACTIVE,
}

State	Meaning	Triggered when
`UNKNOWN`	Can't determine wearable status	Permission denied or Samsung Health unavailable
`NO_DEVICE_LIKELY`	Permission granted but no data ever	No historical data in the past 365 days
`DEVICE_PRESENT_NOT_WORN_RECENTLY`	Device exists but idle	Historical data exists, but nothing in the last 3 days
`ACTIVE`	Wearable is syncing	Recent data present (last 3 days)

Why Four States?¶

A critical design insight: absence of recent data ≠ absence of a wearable.

A user may have a Galaxy Watch but simply not worn it for a few days — left it charging, took a break, or forgot. If the app concluded NO_DEVICE_LIKELY from that, it would wrongly hide wearable features and ask for manual entry from someone who has a perfectly good watch.

By distinguishing DEVICE_PRESENT_NOT_WORN_RECENTLY from NO_DEVICE_LIKELY, the app can show a gentle nudge ("wear your watch again") instead of removing the feature entirely.

Detection Logic¶

SamsungHealthDataSource uses two independent time-window probes per metric:

Probe	Window	Determines
`hasHistoricalData(metric)`	365 days back	Whether any device has ever written this metric
`hasRecentData(metric)`	3 days back	Whether the wearable is actively syncing

Combined:

permission not granted → UNKNOWN
permission granted + no historical → NO_DEVICE_LIKELY
permission granted + historical + no recent → DEVICE_PRESENT_NOT_WORN_RECENTLY
permission granted + recent data → ACTIVE

Usage in the App¶

Onboarding¶

The Permissions step (OnboardingStep.PERMISSIONS) shows one PermissionStatusRow per metric, each displaying its current WearableSignal. This gives the user immediate feedback on what the app can and can't see.

Manual Data Step¶

OnboardingStep.MANUAL_DATA uses the signal to decide what to ask:

ACTIVE → skip the manual slider (wearable covers it)
DEVICE_PRESENT_NOT_WORN_RECENTLY → skip (device is present; the user can re-wear it)
NO_DEVICE_LIKELY or UNKNOWN → show the manual slider

Home Dashboard¶

If any metric is DEVICE_PRESENT_NOT_WORN_RECENTLY, HomeViewModel sets showWearableNudge = true and the nudge card is shown on the Home screen for today.

Simulation¶

SimulationRepository uses the signal to determine wearableCoverageDays and basedOnManualFallbacks, which directly affect SimulationConfidence.